Multiple location dimming system
First Claim
1. A load control device for controlling the amount of power delivered from an AC power source to an electrical load, the load control device comprising:
- a first controllably conductive device coupled in series electrical connection between the AC power source and the electrical load for controlling the amount of power delivered to the load, the first controllably conductive device having a control input;
a sensing circuit operable to provide a control signal representative of a first electrical characteristic of the load control device; and
a first controller coupled to the control input of the first controllably conductive device and operable to receive the control signal from the sensing circuit;
wherein the load control device is operable to be coupled to a second load control device having a second controllably conductive device, the second controllably conductive device coupled in parallel electrical connection with the first controllably conductive device, the first controller operable to determine when the second controllably conductive device changes between a non-conductive state and a conductive state in response to the control signal from the sensing circuit.
1 Assignment
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Accused Products
Abstract
A multiple location dimming system comprises a plurality of dimmers coupled between an AC power source and a lighting load. Each of the plurality of dimmers is operable to control the intensity of the lighting load and comprises a controllably conductive device, e.g., a triac. The triacs of the plurality of dimmers are coupled in parallel electrical connection. Only an active one of the dimmers is operable to conduct a load current to the lighting load at any given time. A passive dimmer is operable to monitor the voltage across its triac in order to determine when the active dimmer is firing its triac. Accordingly, the passive dimmer is operable to fire its triac before the active dimmer fires its triac in order to “take over” control of the lighting load from the active dimmer to become the next active dimmer. Further, the passive dimmer is operable to determine the amount of power being delivered to the load and display this information on one or more status indicators.
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Citations
35 Claims
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1. A load control device for controlling the amount of power delivered from an AC power source to an electrical load, the load control device comprising:
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a first controllably conductive device coupled in series electrical connection between the AC power source and the electrical load for controlling the amount of power delivered to the load, the first controllably conductive device having a control input; a sensing circuit operable to provide a control signal representative of a first electrical characteristic of the load control device; and a first controller coupled to the control input of the first controllably conductive device and operable to receive the control signal from the sensing circuit; wherein the load control device is operable to be coupled to a second load control device having a second controllably conductive device, the second controllably conductive device coupled in parallel electrical connection with the first controllably conductive device, the first controller operable to determine when the second controllably conductive device changes between a non-conductive state and a conductive state in response to the control signal from the sensing circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A load control device for controlling the amount of power delivered from an AC power source to an electrical load, the load control device comprising:
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a controllably conductive device coupled in series electrical connection between the AC power source and the electrical load for controlling the amount of power delivered to the load by conducting current to the electrical load for a first period of time each half-cycle of the AC power source, the controllably conductive device having a control input; a voltage monitoring circuit coupled in parallel with the controllably conductive device and operable to provide a control signal representative of a voltage developed across the controllably conductive device; and a controller coupled to the control input of the controllably conductive device and operable to receive the control signal from the voltage monitoring circuit, the controller operable to determine whether the voltage across the controllably conductive device is a substantially low voltage at approximately the beginning of the first period of time.
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25. A method of controlling the amount of power delivered from an AC power source to an electrical load, the method comprising the steps of:
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monitoring a first electrical characteristic of a first load control device, the first load control device comprising a first controllably conductive device coupled between the AC power source and the electrical load; monitoring a second electrical characteristic of a second load control device, the second load control device comprising a second controllably conductive device coupled between the AC power source and the electrical load and in parallel electrical connection with the first controllably conductive device of the first load control device; the first load control device rendering the first controllably conductive device to be conductive at a first time after a zero-crossing during a first half-cycle of the AC power source; the second load control device determining the first time during the first half-cycle in response to the second electrical characteristic; the second load control device rendering the second controllably conductive at a second time after a zero-crossing during a second subsequent half-cycle, the second time occurring before the first time during the second half-cycle; the first load control device determining that the second load control device rendering the second controllably conductive device conductive at the second time; and the first load control device rendering the first controllably conductive device non-conductive in response to determining that the second load control device rendered the second controllably conductive device conductive at the second time. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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34. A method of controlling the amount of power delivered from an AC power source to an electrical load, the method comprising the steps of:
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monitoring the magnitude of a first voltage across a first dimmer, the first dimmer comprising a first controllably conductive device coupled between the AC power source and the electrical load; monitoring the magnitude of a second voltage across a second dimmer, the second dimmer comprising a second controllably conductive device coupled between the AC power source and the electrical load and in parallel electrical connection with the first controllably conductive device of the first dimmer; the first dimmer controlling the first controllably conductive device to be conductive for a first period of time during a first half-cycle of the AC power source; the second dimmer determining the first period of time in response to the magnitude of the second voltage; the second dimmer rendering the second controllably conductive for a second period of time greater than the first period of time during a second subsequent half-cycle; the first dimmer determining that the second dimmer rendering the second controllably conductive device conductive for the second period of time; and the first dimmer rendering the first controllably conductive device non-conductive in response to determining that the second dimmer rendered the second controllably conductive device conductive for the second period of time.
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35. A method of controlling the amount of power delivered from an AC power source to an electrical load, the method comprising the steps of:
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coupling a plurality of dimmers between the AC power source and the electrical load, the dimmer each comprising a controllably conductive device, the plurality of dimmers coupled such that the controllably conductive devices are coupled in parallel electrical connection; controlling a first one of the plurality of controllably conductive devices to be conductive for a first period of time during a first half-cycle of the AC power source; controlling a second one of the plurality of controllably conductive devices to be conductive for a second period of time greater than the first period of time during a second subsequent half-cycle of the AC power source; and subsequently controlling the first one of the of the plurality of controllably conductive devices to be non-conductive in response to the step of controlling a second one of the plurality of controllably conductive devices to be conductive for a second period of time greater than the first period of time.
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Specification